161538720 has 192 divisors, whose sum is σ = 587575296. Its totient is φ = 36541440.

The previous prime is 161538691. The next prime is 161538721. The reversal of 161538720 is 27835161.

It is not an unprimeable number, because it can be changed into a prime (161538721) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 439977 + ... + 440343.

It is an arithmetic number, because the mean of its divisors is an integer number (3060288).

Almost surely, 2^161538720 is an apocalyptic number.

161538720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161538720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (293787648).

161538720 is an abundant number, since it is smaller than the sum of its proper divisors (426036576).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161538720 is a wasteful number, since it uses less digits than its factorization.

161538720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 523 (or 515 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 33.

The square root of 161538720 is about 12709.7883538633. The cubic root of 161538720 is about 544.6182777170.

The spelling of 161538720 in words is "one hundred sixty-one million, five hundred thirty-eight thousand, seven hundred twenty".